Benzedrine is the trade name of the racemic mixture of amphetamine (dl-amphetamine). It was marketed under this brandname in the USA by Smith, Kline and French in the form of inhalers, starting in 1928. Benzedrine was used to enlarge nasal and bronchial passages and it is closely related to other stimulants produced later, such as Dexedrine (d-amphetamine) and methamphetamine.

Early users of the Benzedrine inhaler discovered that it had a euphoric stimulant effect, resulting in it being one of the earliest synthetic stimulants to be widely used for recreational (i.e., non-medical) purposes. Even though this drug was intended for inhalation, many people abused it by cracking the container open and swallowing the paper strip inside, which was covered in Benzedrine. The strips were often rolled into small balls and swallowed, or taken with coffee or alcohol. The drug was often referred to as "Bennies" by users and in literature.

Because of the stimulant side effect, physicians discovered that amphetamine could also be used to treat narcolepsy. This led to the production of Benzedrine in tablet form.

In the 1940s and 1950s reports began to emerge about the abuse of Benzedrine inhalers, and in 1949, doctors began to move away from prescribing Benzedrine as a bronchodilator and appetite suppressant. In 1959, the FDA made it a prescription drug in the United States. Benzedrine and derived amphetamines were used as a stimulant for armed forces in World War II and Vietnam.

When Benzedrine became a controlled substance, it was replaced by a less potent stimulant drug, Propylhexedrine (also known as Hexahydromethamphetamine). Propylhexedrine was also manufactured by Smith, Kline and French and was marketed under the name Benzedrex. Although Benzedrex is not as potent as Benzedrine, it still has the potential for abuse and has been the cause of death by intravenous use. The Benzedrex inhaler is still available today, but is no longer manufactured by Smith, Kline and French.

Benzedrine should not be confused with the fundamentally different substance Benzphetamine.